1. Field of the Invention
This invention relates to an optical recording disc, whether of the compact disc type or not, from which audio and/or visual information recorded therein can be optically read out.
2. Description of the Prior Art
Recently, in the field of music recording mediums, compact discs known as such are gradually taking the place of conventional discs having groove in which audio to analog information is recorded. A compact disc is described in detail in "Housou Gijutsu (Broadcasting Technologies)", No. 3, 1981, pp. 316-317, and "Nikkei Electronics", Aug. 17, 1981. The compact disc has a bit string formed on a transparent circular substrate and which is recorded audio digital information, an aluminum film being deposited on the surface of the bit string from a surface of a side opposite to the aluminum film, and reflected light from the aluminum film is so utilized as to read out the recorded sound information. Since the compact disc has a high information recording density, it can record more than one hour long music on only one side. It is possible to record information on both sides of the compact disc considering from the relevant principle of recording as well as from the constructional design of any playback device for use with such disc. However, for certain commerical reasons and/or for the reason that double-side recording requires an excessively long period of time for playback, compact discs now available on the market are those having information recorded on one side only. The other side of such disc is used for same purpose as a label on an analog disc of the conventional type. That is, the name of manufactures of the disc, a brand name, title of music, name of performer, etc. are printed on one such side as is independent of the playback side.
As is the case with conventional analog discs, compact discs are often used for gift purposes. However, since a compact disc is small in size as compared with an analog disc, no card of any suitable size on which a relevant message is written or printed is available which is to accompany the compact disc as a gift.
Another problem is that, unlike a jacket for an analog disc, a case for a compact disc has no room for accommodating such card, the face of which often leads to the loss of a card accompanying the compact disc.